Screw-cutting tool



(No Model.)

W. HUTGHESON. SCREW CUTTING TOOL.

No. 453,811. Patented June 9,1891.

1! AHEiA 1 WITNESSES: NTOR:

ATTORNEY.

XVILLIAM IIUTCIIESON, OF BALTIMORE, MARYLAND.

SCREVV-CUTTING TOOL.

SPECIFICATION forming part of Letters Patent No. 458,811, dated June 9,1891.

Application filed October 28,1890- serial No. 369,555. (No model.)

To all whom it may concern:

Be it known that 1, WILLIAM IIUToHEsoN, a citizen of the United States,residing at Baltimore, in the State of Marylandyhave invented certainnew and useful Improvements in Screw-Cutting Tools, of which thefollowing is a specification.

My invention relates to an improvement in that class of screw-cuttingtools in which the dies are automatically thrown off of the screw whenthe required length of thread has been cut; and the main object in viewis to produce a more simple, cheap, and practical construction than hasheretofore been known. I attain this result by the mechanism illustratedin the accompanying drawings, in whicl1- Figure 1 represents a top viewof my improved tool; Fig. 2, a side elevation of the same; Fig. 8, avertical longitudinal section; Fig. at, an end view showing thedie-holding jaws closed, and Fig. 5 a similar view showing the jawsthrown open. I

Referring to the drawings, the letter A i11- dicates the tubular stockof the tool, whichis made with a solid reduced end a, which adapts itfor insertion in one of the centers of a lathe. Across the outer end ofthis stock is arranged a pair of jaws B, which are hinged together by abolt or screw Z2, which also extends into the lower part of the stock,and said jaws shut against each other around a stop-pin c, whichprojects from the face of the stock and limits the movement of the jaws,so that their line of juncture will come directly across the center ofthe stock and intersect the axis of the same. The jaws are actuated awayfrom each other by a coinpression-spring 0, which is secured at itsopposite ends on pins cl, which project from the rear sides of the jaws,and said spring extends around the outside of the stock, beingsubstantially semicircular in general outline. The jaws are providedwith extensions c of reduced width, which project beyond the stock, andsaid jaws are held closed by a curved lever E, having a forked orY-shaped end 6, which is adapted to embrace the extensions e, which havetapering side faces 6 and can thus be wedged in said Y, whereby the jawsare held tightly closed. The lever E is curved and extends through alengthwise slot E, running vertically through the center of the stock,and thus across the bore of the same, and said lever has its fulcrum atits end in a cleat f, secured to the under side of the stock andextending over said slot. A straight bar F is contained within the boreof the stock, extending lengthwise therewith, and said bar runs througha corresponding opening in the lever C, and is adj ustably secured tothe latter by a set-screw g, which shows through a side opening g in thestock, so that access may be had for lengthwise adjustment of the bar F.The end of the setscrew 9 impinges against the bar F. The latterprojects into the mouth of the stock, coming directly behind the openingin the cutting-dies and constitutes a trigger, as herein afterexplained.

The springjaws before mentioned carry dies G, which are fitted indovetailed crossways G in said jaws, and each die is rendered adjustabletherein to cut different-size screwthreads or for a v deeper or lightercut by means of a thu1nb-screw H, having a quick thread and operatingina box 71. at the center of a bridge I, spanning the dovetailed recess G.The thumb-screw has a narrow neck t' at its inner end, and beyond thisan enlarged head t" is formed, and in the die a corresponding recess 7?is provided, which extends back from the front face of said die, and isadapted to contain said head and reduced neck, whereby the manipulationof the thumb-screw causes the die to advance or recede. The bridge I ispivotally secured at one end to the jaw bya screwj and at its oppositeend is formed into a hook 7t, which engages a pin 7;, projecting fromthe jaw, and when thus secured the bridge extends across the end of thedie, and the inner end of the thumb-screw ll engages the recess in thelatter; but if it is desired to remove the die G for the substitution ofanother or for any other purpose the hooked end of the bridge can bereadily disengaged from the pin 70', and said bridge can then be shiftedon its pivot j to clear the die, when the latter can be easily removed.Suitable set-screws on will be provided at the side of the dovetailedrecess to securely hold the dies in position after they have beenadjusted. A stop-lug Z projects from the side of the stock A adjacent tothe pivot Z), on which the jaws turn, and

prevents said jaws from swinging off the end of the stock.

The preferred construction of my device having been set forth, I willnext proceed to describe its operation. During the threadcutting processthe die-carrying jaws B will be held tightly closed by the forked leverE in the manner previously explained; but the bar or trigger F has beenso adjusted that when the desired length of thread has been cut the endof the screw which is being cut will abut against or press saidtrigger-bar and push it back, whereby the lever E will also be thrownback and its upper forked end e released from the j aws, which will thenspring open and instantly stop the cutting of the thread. By adjustingthe bar or trig'gerF by means of the set-screw g any desired length ofscrew-thread can be out, the action of the cutting-dies beingautomatically stopped at the proper moment.

It will be evident that changes which might suggest themselves to askilled mechanic could be resorted to without departing from the spiritand scope of my invention, and hence the same is not limited to theexact construction shown.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In a screw-cutting tool, the combination of a suitable stock,spring-actuated pivotal jaws carrying cutting-dies and occupying a planeat right angles to the axis of said stock, a lever fulcrumed to thestock behind the said die-carrying jaws and adapted to engage the sameand hold them together, and a trigger-for automatically releasing saidlever when the desired length of thread has been cut on the screw.

2. In a screw-cutting tool, the combination of a hollow stock,die-carrying jaws, springactuated away from each other and pivoted tooccupy a plane at right angles to the axis of said stock, a forked leverto hold said jaws together, and a trigger connected to said 1ever andcontained within the hollow stock with its end behind the cutting-dies,whereby the end of the screw which is being cut will press said trigger,and thereby release the jaws.

3. In a screw-cutting tool, the combination of a hollow stock, a pair ofdie-carrying jaws, spring-actuated away from each other and pivoted tosaid stock to occupy a plane at right angles to the axis of the latterand provided with suitable extensions, a lever having a forked endembracing said extensions to hold the jaws together, said leverextending crosswise of the hollow stock, and a trigger-bar adjustablysecured to the lever and extending behind the cutting-dies, whereby thescrew which is being cut will strike said trigger, and thereby releasethe jaws, in the manner described.

4:. In a screw-cutting tool, the combination of a sliding cutting-diecarried by a pivotal holder B, and a bridge attached to the dieholderand extending across the end of the die and carrying a thumb-screw whichis loosely connected to the end of the cuttingdic, as set forth.

In testimony whereof I affix my signature in the presence of twowitnesses.

WILLIAM HUTCHESON.

Witnesses:

ARTHUR O. BABENDREIER, JNo. T. MADDox.

